Going from carb to injection

[SKoob]

I have a 1.2 car engine, and was wondering if fitting the injection, wud give me a gain or loss in perfromance?

[Nova-Boy]

the 1.2 carb has 10bhp more than the in jection. Fitting an injection system off a 1.2 will decrease your power. This is due to the fact that its a singel point injection.

If it were a 1.4sr then perhaps putting a multi point injection would improve performance over a carb. (unless you put twin 40's on it!! :twisted: )

[Aragorn]

u cant make a statement like that cos its not a fair comparison

the spi's haave shitey heads, shite cams and also the cat

fitting the spi system alone to a carbed engine shoudl cetrainly not lose any power as long as u make sure the inlet manifold matches up properly with the 1200 carb head

u may even gain some ever so slightly

[RobHardyUK]

I have a 1.2 car engine, and was wondering if fitting the injection, wud give me a gain or loss in perfromance?

why would you want to fit the injection?

[Snowface]

you'd have to wire it all in including ECU. Why not jest go from 1.2 carb to 1.3/1.4? Much easier.

[Nova-Boy]

u cant make a statement like that cos its not a fair comparison

the spi's haave shitey heads, shite cams and also the cat

fitting the spi system alone to a carbed engine shoudl cetrainly not lose any power as long as u make sure the inlet manifold matches up properly with the 1200 carb head

u may even gain some ever so slightly

Fair enough. I stand corrected. :oops:

[Aragorn]

ooh i forgot to mention the advantages of injection...

perfect fuelling
no cold starting issues
no chokes
no setting up
no freezing up with induction kit
smoother power delivery
faster throttle response

[Euan]

is there any injection system that would fit onto my 1.3sr without losing any power. am fed up of carbs!

[Aragorn]

ive been planning summat like this for a while now

basically im using a GTE head and injection system along with the wiring loom etc on a 1400 SR block

if it all works like it should then the answer to your question is YES and you'll prolly gain power since the 1600 head has bigger valves and better flowed than the 1300 one

[SKoob]

Cus in the winter i don't want the hassle of a choke, but this is irelavent now as I have bought a 1.3 SR with the headgasket done, so gotta get that sorted :D

[Euan]

looking forward to your answer. sounds very interesting!

what about an sri head etc. would this be better/worse

[Snowface]

basically im using a GTE head and injection system along with the wiring loom etc on a 1400 SR block

think it will have to be an SRi block because the GTE/GSI and SRI have larger valves than the others. Not 100% sure though.

[Aragorn]

valves are in the head not the block :|

its been done in the past (brain on here im sure is one of the folks who have done it) so i know it should work fine

[rgv_stu]

aragorn is correct except the carb has a faster throttle response

[Aragorn]

40's may

but u cant compare 40s to summat like bosch jetronic


40's vs TB's = TB's is faster

2e3 vs Bosch Jetronic = Jetronic faster

in both cases - ie standard and aftermarket the injection wins out since its got much more control over the fuelling

[Euan]

when fitting it an engine not designed for injection wont it be a problem to put the sensors etc in place

(i know fuck all bout injection so prob talkin crap)

[rgv_stu]

well your wrong aragorn
due to the fact injection takes time b4 it responds to your foot actions
thewreis nealy allways a delay b4 revs increase on an injection engine with a carb its instantanious hence a better throttle responce

but yes fuel metering etc is far better on injection thats why they run better and more economically

[Aragorn]

the problem aint quite as simple as that

when u plonk the foot on injection the throttle poisiton sensors INSTANTLY know your foots on the floor and inject the exact amount of fuel required at WOT

on a carb u put the boot to the floor it takes a few thousanths of a second for the airflow to pick up and being PULLING the fuel thru the jets etc and into the engine plus due to the fact that the carb is gonna have a bigger fuel surge once it does start delivering fuel your gonna lose a bit of power and response there too

to compare carbs vs injection fairly the only real way is TB's vs say 40's

u cant really compare a 2e3 or 32/34 to a Tuned port injection system since they are soo different in design

a comparison between summat like a 1b1 and the throttle body injection used in the 1.2i would be a fairer test but the other factors in the engine such as the SPi's shitey head and shitey cam and also the cat would have to be removed before the test was fair

[Dicko]

aragorn is completely correct

[SKoob]

well i was thinking seeing as me car doesn't have a cat and is a carb engine, i might get a gain in power, plus make winter running a dream

[Aragorn]

youll need a good few things for the conversion tho

first off - a donor car

your gonna need to get the entire loom out and strip out the stuff for the useless shite like lights and horn etc etc

then for the actual engine

the 1200i uses different ports so u may wanna get somone (or yourself) to machine the ports out on the inlet manifold to match your head

then u will need an exhuast manifold from an injection car - best bet would be to get one from a SRi or 1993 multec GSi since they have the required hole for the lambda probe but also have twin downpipes

couple that with an SRi/GTE/GSi manifold and GTE center section and thats the zorst sorted

you'll then need the SPi fuel tank and lines and thats you

just wire it all up and it should work

wiring will be tricky tho - will garuntee that - unless your really good with that kinda thing - in which case it will just be fiddly and time consuming :D

[rgv_stu]

well i still say he is wrong
standard injection v standard carb
initial responce is still in the carbs favour
performance is in the injections favour

[Aragorn]

ok forgive the mike oxford style double posting :D

but...

ive just had a browse of the EPC and it turns out the 16nz engine used in 1.6 cavvy SPi's has the same cathedral style ports as the 1.2 carb head

meaning if u got the inlet manifold from the cavvy

it would bolt streight onto your head wihtout fiddling with anything

edit: that means u wouldnt need to faff around porting out the original inlet manifold

[Euan]

if i wanted to maintain good performance what would head etc would it be best to get. for my 1.3sr?

just found out my head is warped got an oil leak from bottom right of head and gettin water in the zorst so need to get sumthin sorted.

how long would a project like this take. is it worth just gettin ma head skimmed just now and leavin the injection to later??

[Aragorn]

get a 1200 carb head - it will up your compressoin and give u some extra poke

[Euan]

what about inlet manifold will i need to change that?

will a 1.2 def giv better results??

[Aragorn]

1200 carb head is identical with the exception of a smaller combustion zone giving a slight increase in compression